In a make-to-stock (MTS) environment, improving estimates of customer demand would improve the trade-off between the cost of inventory and the level of customer service. MTS is a production strategy that manufactures products in anticipation of customer demand, based on forecasts. The main challenge of MTS is to balance the inventory costs and the customer service levels. Inventory costs include holding costs, ordering costs, and obsolescence costs. Customer service levels measure the ability to meet customer demand without delay or stockout. A trade-off exists between these two objectives, as higher inventory levels can increase customer service levels but also increase inventory costs, and vice versa.

Improving estimates of customer demand can help reduce the trade-off between inventory costs and customer service levels, as it can lead to more accurate production planning and inventory management. By forecasting demand more accurately, a company can avoid overproduction or underproduction, which can result in excess inventory or stockouts, respectively. By producing the right amount of products at the right time, a company can lower its inventory costs and increase its customer service levels.

Eliminating raw material stockouts would not improve the trade-off between inventory costs and customer service levels in a MTS environment, as it would not affect the finished goods inventory or the customer demand. Raw material stockouts are a supply issue that can disrupt the production process and cause delays or shortages in the finished goods. However, they do not directly impact the inventory costs or the customer service levels of the finished goods, which are determined by the demand forecasts and the production plans.

Decreasing the frozen time zone would not improve the trade-off between inventory costs and customer service levels in a MTS environment, as it would increase the variability and uncertainty in the production process. The frozen time zone is the period of time in which no changes can be made to the production schedule, as it is considered fixed and final. Decreasing the frozen time zone would allow more flexibility and responsiveness to changes in demand or supply, but it would also increase the risk of errors, disruptions, or inefficiencies in the production process. This could resultin higher production costs, lower quality, or longer lead times, which could negatively affect the inventory costs and the customer service levels.

Reducing manufacturing overtime would not improve the trade-off between inventory costs and customer service levels in a MTS environment, as it would reduce the production capacity and output. Manufacturing overtime is a way of increasing the production capacity and output by extending the working hours of the production resources, such as labor or equipment. Reducing manufacturing overtime would lower the production costs, but it would also lower the production output. This could result in insufficient inventory to meet customer demand, which could lower the customer service levels. References := Make-to-Stock (MTS) Definition, Make-to-Stock (MTS) vs Make-to-Order (MTO) | TradeGecko, Value Creation: Assessing the Cost-Service Trade-off